Kurt Baron von Plettenberg (1891-1945) was the descendant of Westphalian aristocratic family, and a soldier in both world wars. His initial expectations of the ‘Third Reich’ were soon disappointed, when he recognized the true nature of the regime. When he accepted the office as general agent of the former Prussian royal house of the Hohenzollerns in 1942, he already belonged to the inner circle of the resistance planning Operation Valkyrie. After the assassination attempt on 20 July 1944, however, he was not immediately discovered as one of the conspirators. Out of consideration for the house of Hohenzollern, which Hitler considered to be his most dangerous internal enemy, he acted more carefully than many others. Yet only a few weeks before the end of the war Plettenberg wss finally denounced and arrested, too. This biography shows for the first time how Kurt von Plettenberg, who belonged to the inner circle of conspirators around Stauffenberg, found a way to prevail during those difficult times and how significantly he influenced the resistance.